Process for the manufacture of working pieces impermeable to gas and vacuum proof



Patented May 20, 1941 UNIE Hans Bernstorfl,

many, or, b

' w ort-on-the-Main, Germesne assignments, to chemical Marketing Company Inc., New York,

No Drawing. Application March 10, 1939, Serial No. 261,134. In Germany March 21, 1938 3 Claims.

My invention relates to-a process for the manufacture of working pieces which are vacuum proof and impermeable to gas, such sheets, discs, plates and the lik' made of beryllium or its alloys with a high content of beryllium.

or the like which moreover are also impermeablev to gas and vacuum proof.

Now I have found that according to my invention working pieces such as sheets, discs and the like which meet these requirements may be manufactured by casting an ingot of the metal orthe alloy, whereby the casting or the ingot is free of occlusions, pores and shrinkhoies and then dividing this solid ingot or casting by sawing, cutting, milling or the like into suitable sheets, discs or the like, such an ingot or casting of beryllium or its alloys which is free of shrinkholes a'nd impermeable may be made, for instance, by melting down the metal under high vacuum, for ex-- ample, under pressures below .01 mm. of mercury, and heating the melt for a period of time such as, for example, for one-half hour to one hour,

as, for instance,

ther'efrpm working pieces such as sheets, discs further treatment or improvement by polishing, coating with electrodeposited coatings or the like.

What I claim is:

1. A process for the manufacture of occlusionfree articles of a material selected from the group consisting of beryllium and beryllium alloys having a high content of beryllium, such assheets. plates and discs, which are impermeable to gas and vacuum-proof, comprising heating abatch of such material under high vacuum to a temperature substantially above the melting point thereof for at least one-half an hour, then allowing the melted batch to cool under high vacuum to form an ingot, dividing this ingot into work pieces of the type of sheets and discs, and then heating such work pieces to temperatures ,between 50 C. and 100 C. below the melting point thereof under a protecting atmosphere and forming such heated work pieces under pressure.

2. A process for the manufacture of occlusionfree articles of a material selected from the group consisting of beryllium and beryllium alloys having a high content of beryllium, such as, sheets. plates and discs, which are impermeable to gas and vacuum-proof, comprising heating a batch of such material under high vacuum to a temto a temperature which is about 100 C. and more above the fusion point thereof, and then cooling down the melted product under high vacuum.

According to my invention these sheets, discs ment, if for instance instead of plain and flat working pieces a curved surface is desired. In the latter case it has been proved advantageous to heat the working pieces in at protecting atmosphere, for instance, hydrogen. to temperatures below the fusion point of beryllium or the alloy and then forming the working pieces with pressure in a suitable manner. Furthermore it has been found that it is advantageous to work at temperatures which lie about 50-to 100 centigrade below the fuslonpoint of the working substance; The pressures which are necessary for the treatment depend mostly on the used temperature and may easily be determined by experiments.

Sheets, discs and so on which are made according to my invention are vacuum proof and even impermeable against high vacuum. They may be utilized, for instance, as windows for-the emission of rays from X-ray tubes. If desired, the working pieces may also be subjected to a and the like may be subjected to a further treatperature' at least about 100 C. over the melting point thereof for at least one-half an hour, then allowing the melted batch to cool under high vacuum to form an ingot, dividing this ingot into work pieces of the type of sheets and discs, and then heating such work pieces to temperatures between C. and 100 C. below the melting point thereof under a protecting atmosphere and forming such heated work pieces under pressure.

3. A process for the manufacture of occulsionfree articles of an alloy of beryllium and aluminum containing more than of beryllium which are impermeable to gases and vacuumproof, comprising heating a batch of such alloy under high vacuum to a temperature substantially above the melting point thereof for at least sheets and discs, and then heating such work pieces to temperatures between 50 C. and C. below the melting point thereof under a protecting atmosphere and forming such heatedwork pieces under pressure.

HANS BERNSTORFF. 

